re·bate 1 
(rēbāt′)
(rēbāt′)n.
A deduction from an amount to be paid or a return of part of an amount given in payment.
tr.v. (rēbāt′, rĭ-bāt) re·bat·ed, re·bat·ing, re·bates
1. To deduct or return (an amount) from a payment or bill.
2. To lessen; diminish.
[From Middle English rebaten, to deduct, from Old French rabattre, rebattre, to reduce, to beat down again : re-, re- + abbattre, to beat down; see ABATE.]
rebat·er n.